You can edit an ETL DataFlow simply by opening it in the Data Center and making the desired changes.
To edit an ETL DataFlow,
Click Data in the toolbar at the top of the screen.
Click in the left-hand navigation pane.
Locate and click the ETL DataFlow you want to edit.
Make any changes you want, then click Save, enter a version description if desired, then click Save to confirm.
When you save a DataFlow, an entry for this version is added to the Versions tab in the Details view for the DataFlow. If you entered a description when saving, that description is shown in the entry for the DataFlow. For more information about versions, see Viewing the Version History for a DataFlow.